The Law and Justice (PiS) government argued that changes are needed to reform an inefficient and sometimes corrupt judicial system, according to public broadcaster TVP.

But the opposition has called the planned reform a "coup d'etat” and claimed PiS wants to stack the court with its own candidates.

Grzegorz Schetyna, the leader of Civic Platform (PO), Poland's main opposition party, said: “Its about PiS being able to introduce dictatorial government”.

Five former Constitutional Tribunal judges have issued a joint statement calling on President Andrzej Duda and MPs to block the changes, saying they could “permanently deprive Poland of the position of a democratic state governed by the rule of law”.

European Commissioner Pierre Moscovici said the changes would not be tolerated.

Poland's former justice minister Borys Budka, currently a PO MP, said the changes would mean the Supreme Court, which is charged with confirming election results, could invalidate them if PiS were to lose.

But PiS MP Marcin Horała has said that the reform would guarantee the separation of powers and ensure a system of checks and balances.

PiS said the broad-reaching changes would effectively create a new Supreme Court.

It added that only “highly qualified” and “ethical” people could become judges and that the court would “enjoy more authority and the trust of citizens”.

PiS supporters have criticised Polish courts for taking too long to hear cases, and have accused judges of being an elite, self-serving clique often out of touch with the problems of ordinary citizens.

The Supreme Court was founded in 1917 as the groundwork for Poland's judicial system was being laid ahead of the country regaining independence after more than a hundred years of foreign occupation. (vb/pk)